Fuse structure for electric circuits



Feb. 25, 1930. J. w. HOOLEY FUSE STRUCTURE FOR ELECTRIC CIRCUITS Filed April 14, 1928 w, a w w N i M WW u N o .7 H 7 H 2 MW 2/ 1 A flfi v4 M W -MMM- a 0 Q Z Q J00 w. w

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Patented Feb. 25, 1930 UNITED STATES JOHN W. HOOLEY, F LARCHMONT, NEW YORK FUSE STRUCTURE FOR ELECTRIC CIRCUITS Application filed April 14,

This invention relates to fuses employed for the protection of electric circuits, and has particular reference to structures in which the fuse member is visible through the shell or casing to note its condition, and which fuse member is renewable if blown.

At present the most popular fuse structure of such type includes a strip of insulating material parallel with the fusible member and which strip is so connected at its ends with other members of the structure, including the usual conducting blades which project from the ends of the casing, that said strip serves to maintain the two blades in Such strip will be hereinafter referred to as the aliner, to readily distinguish it from the fuse strip which is alongside thereof.

In such popular structure both the aliner and the fuse strip are fiat and in planes parallel with the projecting end blades. Therefore, when the device is mounted with the end blades engaged between the usual holding clips, a person standing in front thereof can see thefuse strip only edgewise and therefore, to make a thorough inspection of the fuse as to its condition, must move to one side or the other. Sometimes the devices are in locations where side views thereof are difficult to obtain.

One of the objects of my invention is to provide devices of the character described but in which the fuse strip is secured or mounted in such position relatively to the plane of the i end blades and the usual holding clips, that ing from the casing is so tortuous that there will be little or no opportunity for flames to be emitted. This is because, as is well-known, the blowing of a fuse often generates gases which must be allowed to escape. In other Words, such devices are ventilated so as to 1928. Serial No. 270,065.

avoid risk of explosion when a fuse blows. If such ventilation is quite free, flames also are likely to be emitted. To prevent the escape of flames although providing sufficient ventilation, I construct the casing with no direct path for the gases, which path, l1eretofore, has usually been quite free alongside the end blades.

lVith the above explained objects in View, my invention consists in the construction and combination of parts substantially as hereinafter described and claimed.

Of the accompanying drawings,

Figures 1 and 2 are views of my improved structure of fuse, partly in section, the two views being substantially at a right angle to each other. a

Figure 3 is a view similar to Figure 1 but omitting the entire casin Figure l illustrates, by face and side views, one of the end caps of the casing.

Figure 5 illustrates, by face and side views, one of the threaded rings of the casing.

Figure 6 illustrates, by face and side views, one of the enclosed slotted disks.

Figure 7 illustrates, by face and end views, one of the innermost slotted disks.

Figure 8 is a face view of the members which are employed to provide tortuous passages for the escape of gases.

Similar reference characters designate similar parts or features in all of the views.

The case comprises a shell 12, of Bakelite or shatter-proof glass, or other transparent ad non-conducting material and having each end threaded to be engaged by the internally threaded portion 18 of a brass or other metal ring which has an externally threaded portion of less diameter than the portion 13. As illustrated by comparing Figures 2 and 5, the portion l l has an iii-turned portion 15 in which is an opening 16 that is non-circular in form.

Fitting the threaded portion 14L is a ringshaped cap 1? 2 and 4) between which and the flange 15 a disk 18 is clamped, said disk having slot 19 (Fig. 6) for the passage of the blade 20 as illustrated by Figure 1.

Secured to the inner face of the disk 18, by rivets or other suitable means, are two semi-disks 21 having substantially the form illustrated by Figure 8, the space between them allowing for the presence therein of a portion of the blade 20, said two semi-disks occupying the non-circular opening 16 in the flange 15 of the ring member, and therefore nonrotatable therein.

The inner face of each member 21 (Figs. 2 and 8) is provided with grooves or slight channels 22 at different distances from the periphery and communicating with each other and with the periphery so as to provide a series of indirect or tortuous passages for the esca e of gases around the outer edges of the mem ers 21 and through said grooves toward the center and then out past the blade 20, such outlets being so indirect as to prevent the emission of flames in the event of the fuse blowing. This structure is the same at each end of the casing.

Mounted on each blade inside of and against the semi-disk 21 is a disk 23 (Figs. 1, 2 and 7) having a slot 24 for the blade 20, the ends of said slot engaging the shoulders 25 of the blade, whereb the disk 23 is su ported on the shouldered portion of the bla e and prevented from rotating.

An important feature of my invention resides in the fact that the inner portions of the blades which are connected by the fuse strip 26 and the non-conducting aliner 27, are not in the same plane with those portions which project from the ends of the casing and which are to be held in the usual conducting clips not necessary to illustrate. Said inner portions are twisted as illustrated at 28 in Figures 1, 2 and 3, so that their inner end portions 29 to which the fuse strip and aliner are attached in any wellknown or preferred manner, will be in planes approximately 90 from the plane of the outer portions of the blades.

As shown by Figures 1 and 2, the twisted portions of the blades are entirely inside of the disks which provide the end closures of the shell, and therefore present no obstacle to the assembling of the parts of the fuse together. That is, all of the disks 18 and 21 can be readily slipped over the outer ends of the blades 20 to position with the two inner disks 23 close to the twisted portions of the blades, and then the end caps 17 are screwed firmly to closing positions.

It will now be understood that when the structure illustrated is mounted with the outer portions of the blades 20 held in the usual clips, with the result that a person in front could view said blades only edgewise, said person can see the face of the fuse and therefore is able to more readily determine the condition of the fuse strip than would be possible by an edgewise view of it.

By the term transparent employed herein for the shell 12, I do not limit myself to a shell of glass or other material which is absolutely transparent. The shell will serve its purpose if it is sufliciently transparent to enable the fuse to be seen through it.

Having now described my invention, I claim:

1. An electric fuse structure having a transparent shell and blades projecting from the ends thereof, end-closing disks mounted on said blades, end caps for holding said disks in position, said blades having portions inside the shell twisted at an angle to the outer projecting portions of the blades, the said twisted portions being entirely inside of said disks, the inner ends of the blades having means for removably connecting a fuse thereto.

2. An electric fuse structure having a shell and closures for the ends of the shell, said closures including removable end caps and fiat members held in place by said caps, said fiat members bein formed with a plurality of channels at difi erent distances from their centers and communicating with each other and with the outer margins thereof to provide indirect passageways for the escape of gases.

3. An electric fuse structure having a shell and closures for the ends of the shell, each of said closures comprising a threaded ring secured to the shell, an end cap screwed to the ring, a disk clamped between the cap and rin and fiat members secured to said disk, sai flat members being formed with a plurality of channels at different distances from their centersv and communicating with each,- other and with the outer margins thereof 5 openings being provided for the passage of" blade members through said end closures. In testimony whereof I have aifixed my signature.

JOHN W. HOOLEY. 

